The present invention relates to a battery and a capacitor, and more particularly to a battery and a capacitor which has electrodes including a quinoxaline resin, so that the battery and capacitor are highly stable chemically and electrically and also thermally stable and further have high capacitances.
In the prior art, it has been known that a conductive martial film is formed on a surface of the electrode such as in a secondary battery and a capacitor. For the negative electrode or cathode, conductive polymers such as polythiophene, polyacetylene, polyphenylene, polypyridine, are available. In order to display the conductivity of those materials, it is necessary to do either oxidation electrochemistry by doping the material with a p-type dopant or reduction electrochemistry by doping the material with an n-type dopant.
Those processes for oxidation or reduction are, however, complicated and also need to use a corrosiveness oxidizing agent such as iodine. Further, If Ixe2x88x92, ClO4xe2x88x92 or NR4+(R=alkyl groups) is used as the dopant, the conductive material becomes unstable chemically and physically due to those dopant. As a result, if the above conductive material is used for the electrode, then the capacity is small and cyclic property is unstable.
The above problems are caused by the doping processes, for which reason there has been developed materials usable for the electrode without doping process, for example, N-oxide polyquinolinediil polymers, polyquinoxalinediil, polymers, polypyridinediil polymers. Those conductive polymers are disclosed in Japanese laid-open patent publications No. 9-3171 and No. 9-124777.
In Journal of Electrochemical Society, vol. 140, pp. 2498-2500, 1993, it is disclosed that polyphenylquinoxaline in a concentrated hydrochloric acid solution causes oxidation and reduction reactions as shown in below general formula (1), where choline ions (Clxe2x88x92) are used as dopant. 
where polymerization degree is at least 5 and Xxe2x88x92 represents Clxe2x88x92.
In Journal of Electrochemical Society, vol. 145, pp. 1193-1196, 1998, it is disclosed that polyphenylquinoxaline displays a conductivity in high degree acidic solution, for example, 37%-hydrochloric acid, 70%-nitric acid, 99%-trifluoro sulfuric acid, 96%-sulfuric acid, whereby charge and discharge are caused in the same mechanism as shown in the above general formula. In a concentrated hydrochloric acid, a constant current charge was made to a film containing polyphenylquinoxaline to have confirmed that a capacitance is measured to be 125 mAh/cm3.
The above conductive material, however, has the following problems. The secondary battery using the conductive material has a structure as shown in FIG. 1. A positive electrode (an anode) 2 and a negative electrode (a cathode) 1 are separated by a separator 3. The positive electrode (anode) 2 is in contact with a second collector 4. The negative electrode (cathode) 3 is in contact with a first collector 4xe2x80x2. The positive and negative electrodes may be formed by applying the above conductive materials on the above collectors 4 and 4xe2x80x2, respectively. The conductive materials such as polyquinolinediil polymers, polyquinoxalinediil, polymers, polypyridinediil polymers are used for the negative electrode 1.
The above conductive materials such as N-oxide polyquinolinediil polymers, polyquinoxalinediil, polymers, polypyridinediil polymers comprise aromatic heterocyclic compounds which show low reactivity in electrolytic solution and have low capacity and further which are soluble to water or organic solvents. For those reasons, if the above conductive materials are used for the secondary battery, then it is possible that the conductive material is eluted into the electrolytic solution whereby the capacity is remarkably reduced.
Polyphenylquinoxaline as one of the above conductive materials has a large molecular weight of monomer as a unit. Polyphenylquinoxaline is further doped with chlorine ions as dopant as shown in the above general formula (1), wherein only two electrons serve in reaction, for which reason, a capacity per a unit volume or a unit weight is small.
In the above circumstances, it had been required to develop novel electrode, battery and capacitor free from the above problem.
Accordingly, it is an object of the present invention to provide a novel electrode free from the above problems.
It is a further object of the present invention to provide a novel electrode which is unlikely to be eluted into an electrolytic solution.
It is a still further object of the present invention to provide a novel battery which has a high capacity in a unit volume.
It is yet a further object of the present invention to provide a novel battery which has a high energy efficiency in a unit volume.
It is further more object of the present invention to provide a novel battery which has a high capacity in a unit weight.
It is yet a further object of the present invention to provide a novel battery which has a high energy efficiency in a unit weight.
It is moreover object of the present invention to provide a novel battery which has a high cyclic property.
It is still more object of the present invention to provide a novel capacitor which has a high capacity.
Additionally, it is an object of the present invention to provide a novel method of forming an electrode free from the above problems.
It is a further object of the present invention to provide a novel method of forming an electrode which is unlikely to be eluted into an electrolytic solution.
It is a still further object of the present invention to provide a novel method of forming a battery which has a high capacity in a unit volume.
It is yet a further object of the present invention to provide a novel method of forming a battery which has a high energy efficiency in a unit volume.
It is further more object of the present invention to provide a novel method of forming a battery which has a high capacity in a unit weight.
It is yet a further object of the present invention to provide a novel method of forming a battery which has a high energy efficiency in a unit weight.
It is moreover object of the present invention to provide a novel method of forming a battery which has a high cyclic property.
It is still more object of the present invention to provide a novel method of forming a capacitor which has a high capacity.
The present invention provides an electrode containing a quinoxaline resin and an electrolyte which includes at least one of sulfuric acid ions and sulfonic acid ions, or the electrolyte which includes cations having ion radius of not more than 3 angstroms.
The above and other objects, features and advantages of the present invention will be apparent from the following descriptions.